Indie rock had seen power duos before: Guv’ner, Royal Trux, Buckingham-Nicks, the Carpenters – but they’d never sounded like Quasi. Drumming like a controlled detonation; mutant blues coming out of an electric harpsichord or guitar by turns. Backwards through the backwoods of AM pop and Pebbles psych to create a new form: bar-room baroque. Honey-golden multitracked vocals and some of the bleakest, black-eyed, black-hearted lyrics put to paper since Lou Reed woke up in a bad mood. And all played with the kind of ramshackle ease that only comes from weeks of practice, months in the van, and serious chops.

Janet Weiss and Sam Coomes first collaborated in 1990 as Motorgoat, but by 1993 they had become Quasi. These initial excursions would later be re-released as Early Recordings, but 1997’s R&B Transmogrification is where they define their double act. On drums and harmonies, Weiss is all low-key Bonham-ie, power with poise. On top Coomes’ Roxichord makes you wonder how the electronic harpsichord never took off, its low-end crunch with top notes sounding like Ray Manzarek with a Superfuzz. A treacherous lyrical undertow is always there, catching you as you sing along to sweet pop hooks about death, hopelessness – or the illusions of the atomic family on ‘Mama, Papa, Baby’: “One plus one plus one is nothing.” Yet musically Coomes and Weiss are always greater than the sum of their parts. They just fit together, like a two-piece jigsaw puzzle. You float out of R&B Transmogrification on the dislocated cosmic guitars of ‘Clouds’, a little transmogrified yourself.

From Weiss’s opening salvo, and the first action-painting splatter of Coomes’ keyboard on ‘Our Happiness is Guaranteed’, Featuring “Birds” is Quasi at their peak, melding jams-kicking rock’n’roll, punk action, and chord shifts that feel like the change of a season. The success of Weiss’s other group, Sleater-Kinney, in the meantime was clearly only firing up, rather than undercutting Quasi. The songs slide from science fictional dystopia on ‘Our Happiness is Guaranteed’ and ‘I Never Want to See You Again’, to wage-slave class war on ‘The Happy Prole’ and ‘Sea Shanty’. As for ‘It’s Hard to Turn Me On’ and ‘California’, how can songs about anhedonia, the inability to experience pleasure, feel so good? Mixing uppers and downers isn’t usually advised, but Weiss and Coomes use it to make a musical space that feels unique to Quasi.

Closing in on the millennium, both feet on the pedals, Field Studiesarrives in 1999. Organ edges out the Roxichord, making for a sound less jagged and more floating – like the protagonist of ‘The Star You Left Behind’, drifting out into an infinite void. Does Field Studies have an Elliott Smith turn to the harmonies? They do share that heady hit of sweet-sour power-pop – or maybe both Quasi and Smith have a Heatmiser influence, given that’s the Portland band that Coomes and Smith had played in together. As one of their biggest fans, ‘Clouds’ was one of Smith’s favourite live covers. And Smith plays bass on three of Field Studies’ tracks, returning the favour for the many live shows in which Weiss and Coomes were his backing group. “I live underground on the dark side of town”, sings Coomes, but Field Studies is brilliantly lit with tunes that positively glow, and if the settings and arrangements are little more orderly than Featuring “Birds”, it’s only to heighten those accents.

The rest is history: Sword of God, Hot Shit!, When the Going Gets Dark, American Gong, and, most recently in 2013, Mole City, the late-arriving Tusk of the American indie tradition, four sprawling sides of old joys and new directions. Don’t stop; never stop. “You won’t live long / but you may write the perfect song” sings Coomes on ‘The Poisoned Well’. Quasi wrote more than a few, so if you don’t know these three albums, come on in: your happiness is guaranteed.